[2/8] fix killing OP_SETVAL instructions

Commit Message

Luc Van Oostenryck Nov. 17, 2016, 2:35 p.m. UTC

Currently, kill_instruction() ignore OP_SETVAL instructions
with the result that some instructions are not optimized away
as expected.

For example, when looking at the output of test-linearize,
the following function:

	static int kill_setval(void)
	{
	l:
		return &&l && 0;
	}

gives the following output:

	kill_setval:
		set.64      %r6 <- .L1
		ret.32      $0

The 'set' instruction is obviously unneeded but nevertheless present.

With the patch, the output is the expected:

	kill_set:
		ret.32      $0

Signed-off-by: Luc Van Oostenryck <[e-mail]>
---
 simplify.c                      | 1 +
 validation/kill-replaced-insn.c | 7 +++++++
 2 files changed, 8 insertions(+)

Patch

diff --git a/simplify.c b/simplify.c
index 85da5bec..d07ca1b1 100644
--- a/simplify.c
+++ b/simplify.c
@@ -195,6 +195,7 @@  void kill_instruction(struct instruction *insn)
 		repeat_phase |= REPEAT_CSE;
 		return;
 
+	case OP_SETVAL:
 	case OP_NOT: case OP_NEG:
 		insn->bb = NULL;
 		kill_use(&insn->src1);
diff --git a/validation/kill-replaced-insn.c b/validation/kill-replaced-insn.c
index be031b6c..92021877 100644
--- a/validation/kill-replaced-insn.c
+++ b/validation/kill-replaced-insn.c
@@ -30,6 +30,12 @@  static int kill_select(int a)
 	return (a ? 1 : 0) && 0;
 }
 
+static int kill_setval(int a)
+{
+l:
+	return &&l && 0;
+}
+
 static int kill_load(int *a)
 {
 	return *a && 0;
@@ -51,4 +57,5 @@  static int kill_store(int *a)
  * check-output-excludes: ptrcast\\.
  * check-output-excludes: fpcast\\.
  * check-output-excludes: sel\\.
+ * check-output-excludes: set\\.
  */